Carburetor arrangement



July 31, 1951 A. B. METSGER CARBURETOR ARRANGEMENT 2 Sheets-Sheet lOriginal Filed July 1, 1943 l 1 .Mer

l ALFRED B, METSGER- @1 @L July 3l, i951 A. B. METSGER 2,562.9202

` CARBURETOR ARRANGEMENT Original Filed July l, 1943 2 Sheets-Sheet 2FIG.5

ALFRED la. MET SGER Patented July 31, 1951 UNITED STATES ATENT OFFICEOriginal application July 1, 1943, Serial No.

493,139. Divided and this application November 30, 1945, Serial No.632,089

(Cl. 13S-46) (Granted under the act of March 3, 1883, as amended April30, 1928; 370 O-. G. 757) Claims.

lThe present invention is intended to permit variation of airow througha carburetor for a given metering suction, for density andcompressibility compensation, and for other purposes; and is a divisionof my application Serial Number 493,139, led July 1, 1943 which hasmatured into Patent No. 2,396,279 issued March 12, 1946.

In accomplishing the above purposes in the present device the followingmeans and or Afea tures are combined to form the complete carburetorarrangement of the present invention.

Some of these means just mentioned comprise a series of devices toaccomplish the result as follows:

In order to permit Venturi area control with low control forces, a servooperated Venturi plate is used;

For giving a mechanical indication of the density of a gas, especiallyair, a device called a density calculator is used;

A means which gives a mechanical indication of the ratio of two gaspressures is used in this present invention, and same is designated apressure ratio calculator;

For producing an angular motion equal to that of an angular input, butwith much greater torque, and deriving operating power from suction andsurrounding gas pressure, a suction servo torque multiplier is used;

In order to automatically connect an air or gas suction line with thegreater of two sources of suction, a suction selector valve is used; and

A device is provided herein which is used for controlling the amount offuel admitted to the carburetor which is dependent upon the pressuresfound in the throat and other parts of the air or gas inlet.

The above features and devices are combined in the present carburetorarrangement to produce a device of singular utility, the features ofwhich Will be more fully explained as the description proceeds herein.

In the drawings forming a part of the present specification:

Fig. 1 is a diagrammatic cross-sectional elevation of the presentinvention showing substantially all the above named parts of same.

Fig. 2 is a longitudinal detail section taken on line 2-2 of Fig. 1, ofa controlled vent and cap used in connection with the Venturi plate ofthe invention.

Fig. 3 is a vertical cross-section on line 3-3 of Fig. 5, which last isa suction torque multiplier forming part of this invention.

y Fig. 4 is a vertical section on line 4--4 of Fig. 5.

^ carburetor inlet passage to an engine.

Fig. 5 is a vertical longitudinal section through the above mentionedsuction servo torque multiplier, used with this invention.

The variable areav Venturi meter In the drawings is provided a variablearea Venturi meter which permits variation of airilow for a givenmetering suction, for density and compressibility compensation and otherpurposes in which numeral I indicates the body of an air The numeral 2represents a Venturi spoon which is pivotally mounted on a pintle 3 andis in the nature of a flat metal plate, having an inclined portion 4 anda curved portion 5 thereon, and which slidably engages in a recess orpocket 6 formed in the body portion of the air vinlet casing 'I asclearly shown in Fig. 1 of the drawings.

It Will be noted that leakage of air is provided against by means ofsealing or packing strips 8 on the end 9 of the Venturi spoon 2 Where itengages against the upper face of the recess 6 mentioned. The form ofthe air inlet casing l' is "shaped at I0, II, and I2, to accommodate thevarious parts necessary in the construction of the device.

The casing 'I has mounted thereon a closed container I3 shaped as shownin Fig. 1 for the purpose of housing various parts of the inventiondescribed herein. The Venturi spoon has a Venturi shape as shown andforms one side of a Venturi passage of preferably rectangularcrosssection, and as above stated is pivoted and movable about thepintle 3 so that when the said plate is moved back and forth by means ofthe servo finger I4, the throat portion I5 of the air inlet I6, can beenlarged or diminished automatically or manually as will be describedbelow.

Numeral II indicates a static throat pressure take-off located in theregion of minimum crosssectional area of the Venturi meter. Impat tubeI8 is arranged to obtain the total inlet pressure in the passage I6 andis used for accurate determination of the air pressure admitted to thecarburetor at I6 as will be fully described herein. A fixed vent 20 inthe wall of the Venturi spoon is positioned in the expanding section ofthe venturi, at such a point that the eiective force or pressure behindthe spoon 2 will overcome by a slight margin the effective force on theworking face of said spoon.

Numeral 2I indicates a controlled ventV which appears inenlargedi'detail in Fig. 2 of the drawings and is positioned in the wallof the Venturi spoon 2 and has a proper size and location relative tothe fixed vent 20 so that it overcomes the effect of the latter andcauses motion of the spoon resulting in an increase of Venturi size atthe throat I thereof when the vent 2| is partially or completely open. Avent control cap 22 is positioned on the servo finger I4 near thecontrol vent 2| as shown in Fig. 2 detail for the purpose of Varying theeifective area of the-control vent 2| by varying the amount of closureof the orifices 24.

In the enlarged detail of the parts 2|, 22, and I4 shown in Fig. 2 ofthe drawings it will be seen that the cylindrically shaped part 22,which is fastened to the finger I4 moves axially with respect to part 2|varying the effective area of openings 2d, for the purpose of varyingthe pressure drop through these openings.

It will be noted that the servo linger I4 is preferably pivoted on thesame axis 3- as the Venturi spoon 2 and may be controlled manually orautomatically witha reciprocatory movement through the seal I I formedin the wall 25 of the casing 1. The seal I reduces leakage through thesaid wall 25 around the servo finger Id. The numeral 26 indicates afixed cam support preferably mounted on the bottom wall 2l of the closedcontainer |3. At point 28 on the support 26 is pivotally mounted a cam29 which is pivotally connected at 30 with a connecting rod 3|. The cam29 has an arced slot 3m therein in which the arm extension 32 of theservo finger Iii engages by means of the pintle 33. It is evident thatthe servo linger I4 and the control vent 2| can be operated by means ofthe connecting'rod 3|, and the actuation of 3| by means of the apparatusshown in the closed container I3 will be fully described below.

In connection with the variable area Venturi meter just described air tobe metered to 'the engine enters the carburetor by passage 34 andthrough the air inlet I6, and ismetered as usualr in a venturi, exceptthat the area of this Vventuri may be varied vmanually or` automaticallyas described herein. The pressure on the outer sidey of the Venturispoon 2 is varied along the direction of airiiow or downward' as shownin Fig. 1 of thedrawings. The fixed vent 29' is placed at a point in thepassage 34 where the fluid pressure' has recovered to an intermediatepressure value. l

until the vent' control cap 22 closes the vent 2|A to Such an extentthat the Venturivspoon is in equilibrium. The Venturi plate 2a then;follows the motion of the vent control cap 22 which last is'controlledby the servo finger I4, the latter being operated manually orautomatically as desired.

The above completes the description of the variable area venturi andthe'operati'on of the Venturi'plate 2a used in connection therewith.

The density calculator" One of the means used in operatingrtheconnecting rod 3| above mentioned comprises whatA Control vent' 2| iffully' open' is called a density calculater which is used to give amechanical indication of the density of the fluid used in the presentdevice especially the air portion thereof. A ratio arm 35 having a slottherein is mounted on a revolvable but fixed pivot or pintle Si withinthe closed oontainer i3 as shown. A slide 38 is adapted to reciprocatein the slot 36 of the ratio arm. A temperature indicator 39 which inthis case is a bimetal coil positions the slide 38 a distance from thepivot point 3l' proportional to the inlet temperature obtained by theinlet 40 from the air inlet It as shown. The pressure bellows Lil has anoperating rod l2 which connects it pivotally with the slide 38 in theratio arm 35 as shown.

Thebellows 4I as it reciprocates according to air pressure gives motionto the rod 42 as is at once seen, and to the ratio arm 35 proportionalto the inlet pressure through part Ml, in a line of about with thedirection of ratio arm 35. The pressure bellows lll, it will be seen,is'pivotally mounted at i3 'in the'support M Acarried-on the inner faceof the wall l.

The angular position'of the ratio arm 35, it will 'be noted, variesapproximately directly as the inlet air pressure around the bellows 4|,andinversely as the corresponding temperature; e. g., it varies as thedensity of the gas or air surrounding the calculator. It is seen'thatthe ratio arm 35 then is mechanically operated according to the pressureand temperature of the' gas or air whose density is being measured. Theangular motion of the ratio arm'35 may be used to position a cam 45 anddrive an output connecting rod 45 by means of .the cam Vfollower 4l, andto effect the operation of the connecting'rod` 3| `by means of the crossrod :18. t is noted that the pintle 3l is a xed axis supported withinthe container I3 but revolvably mounted therein, and 'the connecting rodli slidably operates' through a fixed support 49.

The cam follower di follows the edge 5llof the cam 45 and is revolvably'mounted at 5| in the end of the connecting rod' 46. The cross rod i8 ispivotally connected to sliding block'd'which is slidablyrengaged' withand recipro'cabl'evthin fixed channel guide 52. likewise pivotallyconnected to'said sliding block '14. are forked to slidably receive thepintles 53 and 5l which are on the ends'of the connecting rods' 45 and58 respectively.'

From the above it is seen that' the pressure'of the air admitted to thechamber of container I3 through inlet il andthe temperature thereof'operates the density calculator 59. The cal# culator has a mechanicaloperating' eife'ct'on'the connecting rod 3 I, and servo finger I t' andtherethrough the movement of the'Venturi spoon l2 isconformably operatedat theV throat iof'the' Venturi meter in accordance with the pressureand temperature of the inlet air from inlet 4D; From thev above itis'seen that the density calculator gives a mechanical indication of thedensityof a gas'or'of air and can' .be mechanically used as one of thefeatures or factors" in the operation of the Venturi spoon 2 andthe'.

venturi.

The pressure ratio calculator Connecting rodv 3| is' The ends of thecross'rod '48"' at 51| and EF ratio calculator which comprises twopressure operated bellows 6I and 82. Bellows 92 is encased in a shell82a and is attached to rod 1I operating through opening 1Ia in shell82a. The action of these two bellows controls the angular movement ofthe ratio arm 63 on the axis or pintle 84 which is xedly and revolvablymounted in the closed container I3. The ratio arm 63 is slotted at 65 asshown and the slide 66 operates slidably therein. It will be noted thatstatic gas pressure in the throat i5 of the venturi is taken at pointsI1 and through the pipe 61 and delivered to the pressure bellows 62 at68. The pressure bellows B2 is carried pivotally at 69 in the ilxedsupport 10, which is mounted on the inner face of the wall ofthe closedcontainer I3. It will be at once seen that as the pressure bellows 62expands or contracts due to the pressure through pipe 61, and affectsthe operating rod 1I which is pivotally mounted at 12 on the slide 68that the ratio arm 83 will be angularly operated about the pivot point64.

The'pressure bellows 6I is actuated by the gas v or air which is withinthe closed container I3 and comprises the following parts. The pressurebellows 8| is enclosed in the cage 13, and moves the cage 13, which isslidably mounted at 16, 19 on the fixed slide, represented by rods 15,15. The wire 11 delivers the response of the pressure bellows 6I to theslide 68 by means of the pulley 18 which is mounted on the xedrevolvable pintle 19 carried in the closed container I3. It is notedthat the portion 88 of the Iguide wire 11 is in line with the directionslot of the ratio arm G3, and the spring 8l keeps the slack out of thewire 11 when the pull in said wire 11 is lessened by the action of thebellows 8l.

It is then seen that the angular movement of the ratio arm 83 on thepintle 84 is controlled by the joint effect of the two pressure bellows6I and 62 and in turn, the cam 82 revolves in an arc about the pintle84. The cam 82 is in continuous engagement with the cam follower 83which is.

pivotally mounted at 89 in the end of the connecting rod 58 beforementioned. The said rod 58 slidably operates in the xed support 85 andby means of the pintle 51 said rod actuates the cross rod d8 and in turnthe connecting rod 3l of the venturi control device by means of the cam29 and its associated parts.

It will be noted that the angle of rotation of the ratio arm 63 variesapproximately directly as the output of the bellows 62 and inversely asthe output of the bellows 6I; e. g., as the ratio of the two pressurebellows outputs. The angular mo. tion of the ratio arm, of course, maybe used to position a cam, such as 82 to drive an output connection rod58 and control the parts of a servo iinger apparatus, or for otherpurposes, such as actuating a suction torque multiplier described below.

Suction torque multiplier The suction torque multiplier I2I justmentioned is intended to produce an angular motion equal to that of anangular input but with much greater torque deriving its operating powerfrom suction gas pressure and from gas pressure surrounding themultiplier device. The device in hand comprises the following parts andis clearly shown in Figs. 3, 4', 5 of the drawings. The input lever 88(which may be the same as ratio arms 35 or 93 above described) isrevolvably mounted on the cylindrical exterior of the valve section 81.Two vent slotsV 88, 88 formed in the input lever 6*I 86 act as controlvalves for this device. The valve section 81 is operable nearly 360degrees, but if less circular travel is required then said degrees ofrevolution of the body 81a of the valve section 81 may be cut down to asector of a cylinder instead of a complete cylinder.

Each of the Valve section vents 89, 89 in section 81 are ducted or leadto one of the suboperating chambers 98, 98 of the multiplier shown inFigs. 3 and 5 clearly, and said vents are controlled by the input lever86, depending on the angular position of said lever 86 on the valvesection 81 as is at-once understood. In the operating chambers 98, 98 islocated the moving division wall 9| which is preferably made integralwith the body of the valve section 81. Centrally of the operatingchambers is positioned a nxed shaft 92 (which may be shafts 31 or 8d ifso arranged), having a hollow center duct 98 therethrough. A fixeddivision wall 94 is part of or rigidly mounted on the central shaft 92.

Restricted vents 95, in the central xed shaft 92 provide communicationfrom the operating chambers 98, 98 to the center or suction duct 93which is connected to a source of suction by means of pipe |88, whichmay be joined to a suction conduit such as II or H5, shown in Fig. 1.

It is seenthat when the input lever 88 is given an angular displacementone of the vents 89 is opened partially or fully to one of the proximatecorresponding slots 88. This vents one of the operating chambers 98, 98to the gas pressure surrounding the device itself, through one of eachof the inlet ducts 98, ducts 88, and 89 shown in Fig. 5 clearly.

It will be noted that when gas pressure is admitted to either of thechambers 98, 98 the body of the valve section 81 which carries the cam91 will be thrown into a new angular position on shaft 92 and operatesaid cam. rEhe moving division wall 9| as well as the iixed divisionwall 9d are suitably packed at points 98 and 99 respectively withreference to the exterior periphery of the xed shaft 92, and theinterior wall of the valve section body 81a respectively, to reduce gaseleakage thereabout. Until the input lever or arm 86 is given an angulardisplacement and whileboth ducts 89, 89 are in closed positions both ofthe operating chambers 98, 98 are at the suction pressure correspondingto that of the suction duct 93 which is directly connected to thesuction pipe IDD. This results from equal venting through the bleederports 95,' 95 in the central shaft 92 communicating with suction duct93. However' when one of the much larger ducts 89, 89 is opened by meansof actuation of the input lever 86, the gas pressure which surrounds thewhole torque multiplier causes a gas flow through duct 96, recess 88,and duct 89, into one of the chambers 98, 98 resulting in a pressureinequality between the two chambers 98, 98.

However, an appreciable flow of gas escapes through bleeder k95 and anaccompanying pressure drop through this bleeder will result, that is tosay, the pressurized chamber 99 is at a higher pressure than the suctionpassage 93. ln this way a pressure inequality is set up between the twochambers 98, 98. The difference in pressure in the chambers 98, 98acting on division wall 9| rotates the body 81a and the valve section 81tending to unregister ducts 89 and 98. It to be noted that ports 95continually vent the pres sure much more slowly than it is built upthrough inlet duct 89. When ducts 89 and 96 become unregistered, theremaining pressure is exhausted through bleeder ports 95 vand therotation of body 87a ceases. As a result, body 87a is rotated an amountapproximately equal to the angular displacement of arm 83.

This movement of the kvalve section'87 and body Sla restores itsoriginal angular position with respect to input arm 86. Little or noexternal gas is now admitted to the chambers 90, 90 through the ductsB9, 89, recesses 33', 83, and pasages- 95, 36; parts accordingly. do'not movel until pressures in chambers 90,V 90 are again unbalanced bymotion of input arm 86. The motion of the cam 97 therefore follows themotion of the input arm S6 by means of forces derived from the relativepressures of the suction pipe `|Y and the gas surrounding the torquemultiplier, controlled as described above. The motion of the body of thevalve section 87a may be used to' operate a cam 97 as shown or to drivean output arm or lever.

It will be noted in the above description two kinds of means are used tooperate the cam followers 47 and .03, and connecting rods 45 and 53.

In the rst instance shown in Fig. 1 of the drawings where no suctiontorque multipliers I2| (Fig. 5) are used, in transmitting motion fromratio arms 35 and 03 to the cam followers 47 and 83 respectively, it isseen, said arms 35 and 63 are required to be rigidly mounted on saidshafts 37 and 64; likewise cams 50 and 82 are required to be rigidlymounted on said respective shafts. Shafts 37 and 54 are themselvesrevolvably mounted in their supports (not shown) so that when ratio arms35 and 63 are angularly moved, said cams are correspondingly operated inorder to actuate the cam followers 47 and 83, and rods 116 and 58. Theselector valve |20, parts H4, H5, and pipes H0 and I I I in this caseare eliminated as they are used only when the torque multipliers I2| areused.

In the second case where suction torque multipliers such as IZI (Figs.3, 4 and 5) are used, conditions are somewhat reversed. The shafts 37and 54 which correspond to theshaft 92 of Figs. 3, 4 and 5 are then notmade revolvable, and the ratio arms 35 and 53 of Fig. 1 (whichcorrespond to input lever 86, Fig. 3), are made revolvable withreference to shafts 37 and 64, as is at once understood from thedescription of suction torque multiplier I2| as explained above. Thecams 50 and 82 are also inade revolvable with reference to the shafts 37and 64 when the torque multiplier is used in connectionwith the deviceshown in Fig. 1 of the drawings.

It will be noted in the first instance above men The suction selectorvalve |20 used with the present invention comprises the following parts.A valve body IIiI is provided having a pair of spaced-apart valve seats|02, |03which are preferably formed integral with the valve body castingISI. in recesses |05, in the-casing and the .spindle However, the

A valve spindle |04 is slidably mountedv retor in Fig. 1 of theVdrawings.

is made shorter in length th'an'the'overall length between the endsrofthe recesses |05 and |06, leaving a space |07 on either-end of thespindle;

according'to the position of the spindle.

The grooves |08a, Ia' insure the proper ventingof the space |07 betweenthe spindle'ends and the ends of the recesses |05, |06 when the valve isin a'closed position on either side of the valve seat |02 or |03.

The inlet ports |08, |09 are connected with pipes H0, III respectively,and suction port H2 connects with the dual ended pipe H3 whichA formstwo branches I I4, H5 leading to the torque multiplier I 2| abovedescribed; The valve heads ror discs H6, H7 are arranged to be incontact with either one of the valve seats |03 or |02, but with only oneat a time.

The net force or pressure on the valve discs I I6, I I7 moves either oneof them and spindle |04 within the valve, toward the side of lower gaspressure as received from pipes H0 or III, seating the valve between thesource of higher pressure such as i 09a, in the drawings, and thesuctionservice connection or suction port I I2. It is.

whichever point in the passage 34 furnishes lower pressure.

The pipes H4 andV H5 lead to the pipe |00l (Fig. 5 of the drawings) ofthe suction torque multipliers I2I above described and one of which ismounted on each axis 37, and S4 if desired of Fig. 1 of the drawings.

The carburetor assembly The various elements and devices described aboveare assembled to form a simplified carbu- The Venturi spoon 2 ispositioned by the servo finger I4 as before described either manually orautomatically,

said nger being mechanically positioned by the.

cam 29. The input to this cam V29T as shown and above described is afunction of the sum of the density and pressure ratio corrections abovedescribed in connection with the devices shown in and about the closedcontainer I3. Cams 50 and 82 which are attached to the torquemultipliers |2I, I2| which are mounted on the shafts 37 and GII, deliver'appropriate indications to the cani followers VI and 83 and thesemotions are transmitted by the connection rods d0 and 58, and added bythe cross rods 43 and then delivered to the connecting vrod 3| whichcontrols thecam 29,

and hence the servo nnger I and the'Venturi spoon 2 as is readilyunderstood.

It will be noted that while the arrangements have been made for the cams50 and 82 of Fig. 1 and the cam 37 of the suction torque multiplier,Fig. 3, to push downward the connection rods Ei and 58 and theconnecting rod 3| by means of the cross arm 48, it is evident thatmeans'must talfen. This is providedfor by means of a coil spring 23which is mounted on the pintle 23 which. Thev is carried by the fixedcam'support 2G. said spring 23 bears againstY the outstanding .arm`

d IrlI of thecam 29 at pointI-IZ and pushes the' Y livered across theair diaphragm connecting rod 3| upwards when permitted so to do by thecams above mentioned.

This carburetor arrangement automatically controls the size of thethroat l5 leading to the inlet passage 34 and places the Venturi spoon 2automatically in position according to the combined operation of thevarious devices such as 59, 60, 3|, I4 as above described. Said deviceswithin the container I3 are, of course, also affected by means of thesuction selector valve as before explained. Suction pressure to drivethe torque multipliers |2| is taken selectively from the Venturi suctionport ||8 or the blower inlet suction port ||9 whichever gives the lesersuction pressure.

The selector valve |20, of course, selects the proper source of suctionfrom the ports H8, or IIS fed to the torque multipliers |2|, |2| on theshafts 3'! and 64 (Fig. l), or hollow shaft 32 of Fig. 5.

The metering pressures Pl and P2, taken through parts I3 and Ilrespectively, are de- |22 in the pressure responsive device |23. Thediaphragm |22 which is preferably of stiff materialk is provided withflexible material at |24, |24 between the central stiff portion thereofand the fixed housing |25 to which it is attached. A central valve stem|25 is mounted at |21 on the diaphragm |22 as shown and a suitableyielding packed orifice |28 is used to prevent leakage around said valvestem where it leaves the device |23 as shown.

On the lower end of the stem 2E is a fuel regulating valve |37 which isseated at |2811 in the fuel charging box |29 and as stated before, thelatter is provided with the fuel charging orifice I9. A second pressureresponsive device |30 surrounds the valve stem 2B between the chargingbox |29 and the device |23. Said device |33 is provided with a stiffdiaphragm |3| which is attached by flexible material at |32, |32 whereit is attached to the walls |33 and |34 of the device ISD. Saiddiaphragm |3| is also rigidly attached at |35 to the Valve stern |26,and it is seen that the two diaphragms |22 and |3| co-act upon the valvestem |26 and the valve |21.

The metering pressure across the fuel orifice |35 is also across thefuel diaphragm |3|, the total forces on the two diaphragms |22 and |3|are automatically balanced by the action of the fuel regulating valve|37 as long as fuel is supplied to the fuel inlet orice I9 undersufficient pressure. Fuel is delivered to the carburetor passage 34through the delivery pipe |38.

A butterfly valve may be inserted in the inlet passage 34 if desired forthe purpose of controlling the flow of air passing to the engine.

From the above description of the Various parts of the presentcarburetor arrangement it is seen that a fuel and air mixture issupplied to the engine through the orifice |39 from the passage 34,which is regulated in proportions by a series of factors and devicesshown and described in the above specification, and which appear in theFigs. l to 5 of the drawings, practically all of which operateautomatically, and provide an almost perfectly balanced fuel and airmixture to the engine, corrected for the effect of pressure, density,temperature and other factors as fully described in the presentspecification.

The invention described herein may be manufactured and used by or forthe Government of the United States of America for governmental 1Gpurposes without the payment of any royalties thereon or therefor.

I claim:

l. In a variable area venturi, means for controlling the cross-sectionalarea of the throat of the venturi, comprising a walled uid carburetorinlet passage having a pocket recess formed therein, a Venturi spoonhaving a xed vent and a controlled vent therein, an end on the saidspoon adapted to reciprocate in the pocket recess, and said spoon beingpivotally mounted in proximate relation to the wall of the carburetorpassage, a servo nger for controlling the operation of the said spoonand the operative action of the controlled vent, and means for operatingthe servo finger through the wall of the inlet passage, therebyreciprocating the Venturi spoon to diminish or enlarge the throat of theventuri, and the passage of fluid therethrough.

2. A device according to claim l in which the means for operating theservo finger comprises an outstanding arm having a pintle mountedthereon, a xed cam support, a cam having a curved slot therein pivotallymounted on Said support, said slot being in operative sliding engagementwith the pintle of the outstanding arm, and means for revolvablyactuating the cam and reciprocating the Venturi spoon in the inletpassage.

3. A device as in claim l in which the controlled vent comprises a pipemounted in the wall of the Venturi spoon and having perforations nearits end, and a closed end on said pipe, said pipe being connected withan opening in the wall of the Venturi spoon for the passage of fluidpressure therethrough; and in which the servo finger in said claim, isprovided with a cylinder-shaped end adapted to control the opened areaof the perforations in the vent pipe, according to the degree ofreciprocation of the servo finger; and in which the means for operatingthe servo finger comprises a rigid outstanding arm, having a pintlethereon, carried by the servo finger, a fixed cam support, a camprovided with a curved slot pivotally mounted on the cam support, saidslot being in engagement with the pintle of the outstanding arm, andmeans for revolvably actuating the cam and reciprocating the Venturispoon in the throat portion of the carburetor passage, for the purposeof varying the cross-sectional area of the said throat portion of theventuri.

4. In a variable area Venturi, an air inlet passage means forcontrolling the cross-sectional area of the throat of the venturi,comprising a walled fluid carburetor inlet passage having a pocketrecess formed therein, a Venturi spoon pivotally mounted in proximaterelation with the wall of the Venturi passage, an inclined ascendingportion in the wall of said spoon having a fixed vent therein, a sharplycurved portion on the spoon connected with the said ascending portion ofsame, a gradually arced portion on the wall of the spoon adapted toreciprocate in the said pocket recess, a controlled vent in the wallofthe spoon, comprising a dead-ended pipe having a number ofperforations therein near said dead or closed end, and an open end onsaid pipe connected with the air inlet passage, a servo finger pivotallymounted in the wall of the inlet passage, a cylinder-shaped end on saidfinger adapted to move axially with respect to the inner end of thedead-ended pipe, for controlling the effective area of the perforationsin the said pipe,

according to the degree of reciprocation of the servo finger, anoutstanding arm on the servo finger, a fixed cam support, a cam having acurved Vslot therein, pivotally mounted on the fixed support, said slotbeing slidably engaged with the end of the outstanding arm of the servofinger, and means for revolvably operatingthe cam to reciprocate theVenturi spoon and thereby control the cross-sectional area of the throatof the Venturi passage, as well as control the amount of fluid underpressure passing through the wall of the Venturi spoon.

5. in a density calculator a pressure bellows pivotally mounted on afixed shaft, and adapted to be operated by the pressure of thefluidsurrounding said bellows, an operating rod reciprocatingly actuatedby said bellows, a slotted ratio arm mounted on a hollow xed shaft, aslide adapted to reciprocate in theratio arm ,slot in accordance withthe temperature surrounding a temperature responsive bimetal coilassociated with said s1ide,-said,pressure bellows and bimetal coilco-acting to effect the arm in arcual movement in accordance with thecombined effect of the pressure bellows and the bimetal coil; incombination with a suction torque multiplier comprising the aforesaidhollow fixed shaft which is provided with a plurality of restrictedvents therein, a body casing revolvably mounted on the central hollowshaft and divided intotwo operating chambers formed by the cooperationof an abutment xed to said shaft and a vane fixed to said casing, avalve section extension on said body having a pair of valve sectionvents formed therein, the beforementioned arm being revolvably mountedon the valve section extension and having a pair of vent slots whichconnect the exterior of the ratio arm with an operating chamber of thetorque multiplier when the said slots arein registration with the slotsof the valve section extension for the purpose of the admission of fluidpressure from the exterior of the device to the operating chambers inthe body of the device, and to overcome the normal pressure in one ofthe operatingrchambers of the torque multiplier which has been admittedthrough the hollowflxed shaft, Aand thus cause the arcual movement ofthe body of the multiplier on its central shaft, and a cam on said bodyadapted to transmit the angular motion of the arm to output devices,

6. A pressure ratio calculator comprising a pressure bellows pivotallymounted on a xed support, a casing surrounding said bellows, anoperating rod slidably mounted in said casing and actuated by saidbellows, an arm having a longitudinal slot therein, revolvably mountedon a second xed support, a slide adapted to reciprocate in said slotpivotally attached to the operating rodga second pressure bellowsmounted on a third xed support, a slidably supported cage attached tothe movable end of the second bellows, a pulley mounted on a fourthfixed support, a wire cable attached to the bellows cage passing oversaid pulley and attached to the slide of the ratio arm, for operatingsaid slide in the arm slot, and a tension spring means mounted on theupper end of the ratio arm and attached to said slide.

7. In a means for operating a Venturi spoon in a carburetor feed device,a pair of revolvable shafts mounted in adjacent relation to each other,an arm rigidly mounted on one'of said shafts, fluid density operatedmeans attached to said arm for arcuately operating said arm and itssupporting shaft, a'cam rigidly vmountedon the density operatedsupporting shaft, a second varm mounted on the companion revolvableshaft, 'fiuid pressure operated means having a motion transmittingmember pivotally and slidably connected with the second-named armandobtaining its pressure from a distant source of uid pressure which isconveyed to and within said means, a Vcompanion fluid pressure operatedmeans responsive to pressure immediately surrounding said companionmeans for sliding said member relative to said second arm, a cam rigidlymounted on the companion shaft, ya-pair of vopposed cam followers eachin engagement with one of the pair of cams named herein, a pair ofopposed axially slidable connecting rods each revolvably attached to acam follower at one end and having a pin fixed at the other end, across-rod having a pair of slots formed on the ends thereof, each ofsaid slots engaging one of said pins for pivotal connection of theabove-named connecting rods, a fixed channel guide, a slidable block inthe said guide pivotally connected with said cross-rod, a fixed camsupport, a slotted cam pivotally mounted on said cam support and havingan extension thereon, a connecting rod pivotally mounted on said camextension, and pivotally connected to the slidable block operating insaid guide, a pivotally mounted Venturi spoon, a servo finger having aservo follow-up connection with said spoon and pivotally mounted on thesame axis with the pivoted end of the Venturi spoon, and means on theservo finger adapted to pivotally operate in the slotof said slottedcam, the whole above described device being adapted to actuate theVenturi spoon in accordance with the combined effect of the density andpressure operated means described herein.

8. ln a suction torque multiplier, a hollow fixed shaft lhaving aplurality of restricted bleeder vents therein, a body casing revolvablymounted on said shaft, and divided into two chambers formed by thecooperation of an abutment xed to said shaft and a vane xed to saidcasing-a valve section extension on said body having a pair of valvesection vents formed therein, ran input lever revolvably mounted on thevalve section and having a pair of vent slots which connect the exteriorof the input lever with one of said operating chambers of the body ofthe device when said slots are in registration with the slots of thevalve section, for the purpose of the admission of gas pressure from theexteriorof the device throughthe hollow fixed shaft to said operatingchamber in the body casing for overcoming the normal pressure in saidcentral chamber of the body casing thereby causing arcual movement ofthe body of the device on its central hollow shaft.

9. In a suction torque multiplier, hollow xed shaft having a pluralityof restricted bleeder vents therein, a body casting revolvably mountedon said fixed shaft and divided into two chambers formed by thecooperation of an abutment xed tosaid shaft and a vane fixed to saidcasing, a valve'section extension on said body casing having a pair `ofvalve section vents formed therein, an input lever revolvably mounted onthe valve section extension having a pair of vent slots, one of each ofwhich'is adapted to connect with one of the valve section extensionvents at a time, each'of said invput lever slots connecting with theexterior of 13 the input lever for the admission of gas pressure fromthe exterior of the device to one of the chambers of the body casing ata time when the input lever vent slots are in registration with the ventslots of the valve section extension.

10. In a density calculator, a pressure bellows pivotally mounted on axed support, an operating rod reciprocatingly actuated by said pressurebellows, a slotted ratio arm mounted on a revolvable support, a slidepivotally connected to said operating rod adapted to operate with areciprocating motion in said slot, a bimetal temperature responsive coilmounted on said ratio arm adapted to impart reciprocatory movement tosaid slide in said ratio arm slot, said pressure bellows and saidbimetal coil acting in cooperative relationship to angularly actuatesaid ratio 14 arm with respect to its revolvable support, cam meansprovided on said revolvable support, and a cam follower associated withsaid cam means adapted to be rotated when said cam means is actuated.

ALFRED B. METSGER.

REFERENCES CITED The following references are of record in the ille ofthis patent:

UNITED STATES PATENTS Number Name Date 668,938 Noordaa Feb. 26, 19061,913,684 Purdy June 13, 1933 2,036,251 Boynton Apr. '1, 1936 2,305,070Butler Dec. 15, 1942

